Question

expend :
(2a-5b-7c)^2
solv step by step​

Answer 1

Answer..✍✍

(2a−5b−7c)2

According to the equation,

(a+b+c)2=a2+b2+c2+2ab+2bc+2ca

So we get,

Using the formula we can it arite it as

(2a−5b−7c)2=(2a)2+(−5b)2+(−7c)2+2(2a)(−5)+2(−5b)(−7c)+2(−7c)(2a)

On further calculation we get,

(2a−5b−7c)2=4a2+25b2+49c2−20ab+70bc−28ca

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Answer 2

Answer:

4a^2+25b^2+49c^2-20ab+70bc-28ca

Step-by-step explanation:

formula-----------------------------------------------------------(a + b + c)^2 = a^2 + b^2 + c^2 + 2ab + 2bc + 2ca

-==(2a-5b-7c)^2=(2a)^2+(-5b)^2+(-7c)^2+2{2a×(-5b)}+2{(-5b)×(-7c)}+2{(-7c)×2a}

============== 4a^2+25b^2+49c^2-20ab+70bc-28ca

your answer is

4a^2+25b^2+49c^2-20ab+70bc-28ca

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